Hackers
This generic and often over-romanticized term applies to computer enthusiasts who take pleasure in gaining access to other people’s computers or networks. Many hackers are content with simply breaking in and leaving their “footprints,” which are joke applications or messages on computer desktops. Other hackers, often referred to as “crackers,” are more malicious, crashing entire computer systems, stealing or damaging confidential data, defacing Web pages, and ultimately disrupting business. Some amateur hackers merely locate hacking tools online and deploy them without much understanding of how they work or their effects.

Unaware Staff
As employees focus on their specific job duties, they often overlook standard network security rules. For example, they might choose passwords that are very simple to remember so that they can log on to their networks easily. However, such passwords might be easy to guess or crack
by hackers using simple common sense or a widely available password cracking software utility. Employees can unconsciously cause other security breaches including the accidental contraction and spreading of computer viruses. One of the most common ways to pick up a virus is from a floppy disk or by downloading files from the Internet. Employees who transport data via floppy disks can unwittingly infect their corporate networks with viruses they picked up from computers in copy centers or libraries. They might not even know if viruses are resident on their PCs. Corporations also face the risk of infection when employees download files, such as PowerPoint presentations, from the Internet. Surprisingly, companies must also be wary of human error. Employees, whether they are computer novices or computer savvy, can make such mistakes as erroneously installing virus protection software or accidentally overlooking warnings regarding security threats.

Disgruntled Staff
Far more unsettling than the prospect of employee error causing harm to a network is the potential for an angry or vengeful staff member to inflict damage. Angry employees, often those who have been reprimanded, fired, or laid off, might vindictively infect their corporate networks with viruses or intentionally delete crucial files. This group is especially dangerous because it is usually far more aware of the network, the value of the information within it, where high-priority information is located, and the safeguards protecting it.

Snoops
Whether content or disgruntled, some employees might also be curious or mischievous. Employees known as “snoops” partake in corporate espionage, gaining unauthorized access to confidential data in order to provide competitors with otherwise inaccessible information. Others are simply satisfying their personal curiosities by accessing private information, such as financial data, a romantic e-mail correspondence between coworkers, or the salary of a colleague. Some of these activities might be relatively harmless, but others, such as previewing private financial, patient, or human resources data, are far more serious, can be damaging to reputations, and can cause financial liability for a company.